The box bottom contains information from its manufacturer, Sun-Lambert Inc of Ridgewood, NY. It also carries a type number, the 5309 part of which is also included on the box front and could be a Penney number, or be part of a standard size system to allow efficient packing of multiple boxes in one order. The box being produced in the US would indicate that it was also packed with toys in that country instead of in Hong Kong meaning toys were sent in bulk to Penney's (a not uncommon practice in those days - Mattel f ex printed all its boxes locally in each country they were sold in, so will also have had components shipped in bulk from Hong Kong insofar as these weren't produced locally as well).
The bottom of the box is taped shut on the inside, perhaps to make sure nothing small might escape. And top and bottom were shut with two hefty brass staples, probably to guarantee it reached the customer unopened through the mail.
Box size
Length
Width
Height
26.3 cm
16 cm
19 cm
10 3/4 in
6.5 in
7 7/8 in